Investigators linked the killing to a robbery just a few hours earlier at the Interstate 95 service plaza in Newark. A description of a vehicle, a black Ford Tarus, in the service center robbery led investigators to an apartment next to the 7-Eleven, where Palmer and Carson were arrested.

Police say two masked men -- Stallings and Palmer -- burst into the 7-Eleven on Four Seasons Parkway on September 12 just before 1 a.m., demanding money. Surveillance video shows that Ullah fully cooperated with the robbers and handed over the cash from the register, but that didn't stop one of the men from shooting the clerk as they were leaving the store. Ullah was pronounced dead at the scene.